The present invention relates to an automobile-seat headrest.
Conventional headrests consist of a padded part slidably mounted on two rods in the seat""s backrest, said rods being inserted in the backrest""s headrest bushes. The padded part contains a support connected to the head rest""s rods.
In general the headrests are configured improperly or inadequately in a vehicle and assume a position matching the driver or passenger. In case of a rear-end collision, a large spacing between the head and the headrest entails pronounced tensile stresses in the neck that may result in substantial injuries to it. A case of improper position in particular results when the headrest is too low on the backrest.
The objective of the present invention is to create a headrest remedying the above defects.
As regards the headrest of the invention, a second support for a displaceable pad is displaceably mounted on the fixed pad, the displaceable pad being adjustable between a retracted position in the said fixed pad and an extended position, and vice versa, the displaceable pad when advanced being moved forward from the fixed pad toward the head of the seated person. The invention furthermore provides a drive device to set the displaceable pad into its extended position.
In one embodiment of the present invention, the displaceable pad when in its advanced position also is raised above the fixed pad. In this manner the displaceable pad not only is displaced relative to the head as regards the sitting position, but also it is raised with respect to the head.
In case of a rear impact on the vehicle, the displaceable pad, having moved toward the back of the driver""s head, assures direct support for the driver""s head and as a result the driver is virtually made safe against the so-called whiplash effect. Following the accident, the headrest may be moved back into its initial, that is the retracted position and shall be operational once more.
A number of designs are applicable to displaceably support the movable headrest at the fixed pad. Preferably a lever linkage shall be used, in particular a spring-loaded parallelogram. Once the spring has been released, for instance from a locked position, the parallelogram linkage is able to advance the displaceable pad and to move it near the back of the head of the seated person. It is understood that in case of impact on said displaceable pad, it may not yield excessively but instead shall absorb said impact. Accordingly in one embodiment of the invention, a stop is used that shall act as a rest for one or more levers of the parallelogram when on account of impact on the displaceable pad a force shall be exerted on it in the direction of the fixed pad. However locking mechanisms also are applicable that shall lock the displaceable and extended pad to absorb a pertinent force. Such locking action then must be eliminated once the displaceable pad must be returned into its rest position.
As mentioned above, the displaceable pad may be spring-loaded into the extended position, or a locking element may be used to lock the spring or the linkage against the spring bias in the retracted position. An appropriate drive device furthermore includes an unlocking element in order to release the lock. This goal may be attained in the present invention by using a cable. This cable must be positioned at a site appropriate for its activation when rear-end impact takes place. Illustratively this feature may be implemented by the pressure exerted by the seated person""s back against the backrest when the vehicle""s rear is impacted.
However the force setting the displaceable pad also may be applied to a component remote from the headrest and by cable force transmission. Again a number of designs are conceivable. One design of the invention employs a drive device with a first and a second element that are mutually displaceable in to-and-fro manner and which are kept apart by a spring that biases the two elements apart. One of said elements guides a carriage linked to a lever of which the other end is linked to the other element. A cable is affixed to the carriage. The carriage shall be displaced when the two elements are mutually moved to-and-fro. The carriage is adjusted in this manner and an adjusting force can be exerted on the cable which in turn sets the displaceable pad into the extended position. The support may be connected to the displaceable pad in the manner already described above.
Preferably the displaceable pad is received in part or in whole in the fixed pad. Accordingly, in one embodiment of the present invention, the fixed support shall exhibit a U-shape and the displaceable support shall be preferably planar, their dimensions being selected in a manner that the displaceable pad when in its rest position shall be received in a matching clearance in the fixed pad.